Method of manufacturing a device substrate and a display device manufactured using the same

ABSTRACT

A device substrate manufacturing method includes forming a debonding layer on a carrier substrate. An inorganic adhesive layer is formed on at least a portion of the debonding layer. A process substrate is formed on the carrier substrate. A device is formed on the process substrate, and the process substrate is separated from the carrier substrate.

CROSS-REFERENCE TO RELATED APPLICATION

This U.S. non-provisional patent application claims priority under 35U.S.C. §119 to Korean Patent Application No. 10-2014-0002950, filed onJan. 9, 2014, the disclosure of which is incorporated by referenceherein in its entirety.

1. TECHNICAL FIELD

The present disclosure relates to a device substrate, and moreparticularly to a method of manufacturing a device substrate and adisplay device manufactured using the same.

2. DISCUSSION OF RELATED ART

A display device may include a flat display panel, such as a liquidcrystal display device, a field emission display device, a plasmadisplay panel device, or an organic light emitting diode display device.A display device may be included in various electronic devices, such as,for example, a television set or a mobile phone. When a display deviceis manufactured using a glass substrate without flexibility, the use ofthe display device may be limited.

In recent years, various attempts have been made to manufacture a curveddisplay device. For example, a curved display device may include aflexible material, such as, for example, a plastic material.

SUMMARY

Exemplary embodiments of the present invention provide a method ofmanufacturing a flexible device substrate.

Exemplary embodiments of the present invention provide a display devicemanufactured using the device substrate manufacturing method.

Exemplary embodiments of the present invention provide a devicesubstrate manufacturing method including forming a debonding layer on acarrier substrate. An inorganic adhesive layer is formed on at least aportion of the debonding layer. A process substrate is formed on thecarrier substrate. A device is formed on the process substrate, and theprocess substrate is separated from the carrier substrate.

The debonding layer may have a hydrophobicity greater than ahydrophobicity of the process substrate.

The debonding layer may include a silane compound. The silane compoundmay include polydimethylsiloxane (PDMS).

The debonding layer may be formed by forming a silane compound layerincluding a self-assembled monolayer on the carrier substrate andcleaning the carrier substrate.

The inorganic adhesive layer may have a hydrophilicity greater than ahydrophilicity of the debonding layer.

The inorganic adhesive layer may include a metal oxide material. Themetal oxide material include of Al₂O₃ and/or AlZnO.

The inorganic adhesive layer may be formed by depositing the metal oxidematerial on the debonding layer.

The inorganic adhesive layer may have an island shape. The inorganicadhesive layer may overlap a portion of the debonding layer.

The inorganic adhesive layer may be formed over an entire surface of thedebonding layer.

The process substrate may be formed by forming a curable polymer layeron the carrier substrate on which the debonding layer and the processsubstrate are formed and curing the curable polymer layer.

The process substrate may include polyethylene terephthalate (PET),polyethylene naphthalate (PEN), polyether sulfone (PES), polycarbonateester (PC), polysulfone, phenolic resin, epoxy resin, polyester,polyimide, polyetherester, polyetheramide, cellulose acetate, aliphaticpolyurethane, polyacrylonitrile, polytetrafluoroethlenes, polyvinylidenefluorides, poly(methyl(x-methacrylates)), aliphatic or cyclicpolyolefin, polyarylate, polyetherimide, polyimide, fluoropolymer (likeTeflon), poly(etherether ketone), poly(ether ketone), poly(ethylenetetrafluoroethylene) fluoropolymer), poly(methyl methacrylate), and/orarylate/methacrylatecopolymer.

The process substrate may include polyimide.

According to an exemplary embodiment of the present invention, a displaydevice includes a first substrate including a first surface and a secondsurface opposite to the first surface. A pixel is disposed on the firstsurface, and a first inorganic adhesive layer is disposed on the secondsurface. The first inorganic adhesive layer is hydrophobic.

The display device includes a second substrate including a third surfacefacing the first substrate and a fourth surface opposite to the thirdsurface. A second inorganic adhesive layer is disposed on the fourthsurface. The second inorganic adhesive layer is hydrophobic.

The first and second inorganic adhesive layers may include a metal oxidematerial. The metal oxide material may include Al₂O₃ and/or AlZnO.

BRIEF DESCRIPTION OF THE DRAWINGS

The above and other features of the present invention will become moreapparent by describing in detail exemplary embodiments thereof, withreference to the accompanying drawings in which:

FIG. 1 is a flowchart describing a manufacturing method of a devicesubstrate according to an exemplary embodiment of the present invention;

FIGS. 2A to 2E are cross-sectional views showing a manufacturing methodof a device substrate according to an exemplary embodiment of thepresent invention:

FIG. 3 is a graph showing a weight of a process substrate as a functionof a temperature in a process substrate manufactured by the devicesubstrate manufacturing method according to an exemplary embodiment ofthe present invention;

FIG. 4 is a cross-sectional view showing an inorganic adhesive layerdisposed on a carrier substrate according to exemplary embodiments ofthe present invention;

FIG. 5 is a cross-sectional view showing a display device manufacturedby a display device manufacturing method according to an exemplaryembodiment of the present invention; and

FIGS. 6A to 6F are cross-sectional views showing the display devicemanufacturing method of FIG. 5.

DETAILED DESCRIPTION

It will be understood that when an element or layer is referred to asbeing “on”, “connected to” or “coupled to” another element or layer, itmay be directly on, connected or coupled to the other element or layeror intervening elements or layers may be present. When an element isreferred to as being “directly on,” “directly connected to” or “directlycoupled to” another element or layer, there might not be any interveningelements or layers present. Like numbers may refer to like elementsthroughout. It will be understood that, although the terms first,second, etc. may be used herein to describe various elements,components, regions, layers and/or sections, these elements, components,regions, layers and/or sections should not be limited by these terms.These terms may be used to distinguish one element, component, region,layer or section from another region, layer or section. Thus, a firstelement, component, region, layer or section in an exemplary embodimentof the present invention may be termed a second element, component,region, layer or section without departing from the teachings of thepresent invention.

Spatially relative terms, such as “beneath”, “below”, “lower”, “above”,“upper” and the like, may be used herein to describe one element orfeature's relationship to another element(s) or feature(s). It will beunderstood that the spatially relative terms may encompass differentorientations of a device in use or operation in addition to theorientation depicted in the figures. For example, if a device in thefigures is turned over, elements described as “below” or “beneath” otherelements or features may then be oriented “above” the other elements orfeatures. Thus, the exemplary term “below” may encompass both anorientation of above and below. For example, the device may be otherwiseoriented (e.g., rotated 90 degrees or to other orientations) and thespatially relative descriptors used herein may be interpretedaccordingly.

The terminology used herein is for the purpose of describing exemplaryembodiments of the present invention and is not intended to be limitingto the present invention. Hereinafter, exemplary embodiments of thepresent invention will be described in more detail below with referenceto the accompanying drawings.

FIG. 1 is a flowchart describing a manufacturing method of a devicesubstrate according to an exemplary embodiment of the present inventionand FIGS. 2A to 2E are cross-sectional views showing a manufacturingmethod of a device substrate according to an exemplary embodiment of thepresent invention. The device substrate manufacturing method accordingto an exemplary embodiment of the present invention will be described inmore detail below with reference to FIGS. 1 and 2A to 2E.

Referring to FIG. 1, the device substrate may be manufactured by forminga debonding layer DBL on a carrier substrate CS (S110), forming aninorganic adhesive layer ADL on the debonding layer DBL (S120), forminga process substrate PS on the carrier substrate CS (S130), forming adevice on the process substrate PS (S140), and separating the processsubstrate PS from the carrier substrate CS (S150).

Referring to FIGS. 1 and 2A, the carrier substrate CS may be preparedand the debonding layer DBL may be formed on the carrier substrate.

The carrier substrate CS may support the process substrate PS and mayhave an area equal to or greater than that of the process substrate PS.

The carrier substrate CS may include glass, crystal, anorganic-inorganic polymer material, or a fiber reinforced plastic.

The carrier substrate CS may be a rigid substrate without flexibility,but the exemplary embodiments of the present invention should not belimited thereto or thereby. That is, a portion of the carrier substrateCS may be flexible according to a process condition.

The debonding layer DBL may be disposed on a surface of the carriersubstrate CS.

The debonding layer DBL may includes a material having a surface energydifferent from that of the process substrate PS. For instance, thedebonding layer DBL may include a material having a hydrophobicitygreater than that of the process substrate PS.

The debonding layer DBL may include a silane compound layer. The silanecompound layer may be a self-assembled monolayer.

The silane compound layer may be formed by pretreating the carriersubstrate CS, forming the self-assembled monolayer on the carriersubstrate CS, and cleaning the carrier substrate CS.

The pretreating process may oxidize a portion of the carrier substrateCS before the surface of the carrier substrate CS is modified, so thatreactivity in a modification reaction may be increased. In an exemplaryembodiment of the present invention, the pretreating process may includea process of treating the surface of the carrier substrate CS using anultraviolet ray or a process of plasma-treating the surface of thecarrier substrate CS using oxygen (O₂) and/or ozone (O₃). Theplasma-treatment process may be performed by loading the carriersubstrate CS into a decompression chamber and injecting oxygen (O₂) orozone (O₃) into the decompression chamber using a plasma injector for apredetermined time, e.g., about 30 seconds to about 60 seconds.

After pretreating the surface of the carrier substrate CS withultraviolet rays, O₂, and/or O₃, an —OH group having high reactivity maybe formed on the surface of the carrier substrate CS. The —OH group mayallow the self-assembled monolayer to be formed and may increase anadhesive force between the self-assembled monolayer and the carriersubstrate CS. The intensity of the ultraviolet rays and the irradiationtime of the ultraviolet rays may be determined depending on the materialused to form the carrier substrate CS.

The pretreatment process may be omitted based on the materials includedin the carrier substrate CS. For example, the pretreatment process maybe omitted when the surface of the carrier substrate CS includes areactive group that reacts with a silane compound of the silane compoundlayer.

The self-assembled monolayer may be formed by providing a compound onthe carrier substrate CS, which interacts with the surface of thecarrier substrate CS to provide a compound having a functional groupcoupled to the surface of the carrier substrate CS in the form ofcovalent bond, hydrogen bond, or chemical absorption, andtwo-dimensionally self-aligning the compound on the carrier substrateCS.

The silane compound used to form the self-assembled monolayer may havethe following chemical formula 1.

In chemical formula 1, Z₁, Z₂, Z₃, and Z₄ may independently denote —H,—CH₃, —Cl, — OCH₃, —OCH₂CH₃, —OCOCH₃ or —OCH₂CH₂CH₃ One or more of Z₁,Z₂, Z₃, and Z₄ may be —H or —CH₃. In an exemplary embodiment of thepresent invention, the silane compound may include polydimethylsiloxane(PDMS).

Silanization of the self-assembled monolayer may be performed in aliquid state or a gaseous state.

A liquid silanization process of the self-assembled monolayer may beperformed by preparing a silane compound solution and coating thecarrier substrate CS with the silane compound solution. The silanecompound solution may include water as a catalyst.

A gaseous silanization process may be performed by loading the carriersubstrate CS into a vacuum chamber maintained in a pressure of about 500Pa together with the silane compound. The vacuum chamber may maintainthe temperature and pressure, which are suitable for vaporizing thesilane compound. For example, a vapor may be injected into the vacuumchamber as a catalyst to allow the silane compound to be self-assembledon the carrier substrate CS after air in the vacuum chamber isdischarged to the outside of the vacuum chamber.

The liquid or gaseous silanization processes, which use water as acatalyst, may be expressed as the following chemical formula 2. Forexample, Z₁ may be a hydrogen atom and each of Z₂, Z₃, and Z₄ may be —Clin chemical formula 2. Portions represented by a box represent thecarrier substrate CS.

The liquid or gaseous silanization processes, which do not use water asa catalyst, may be expressed as the following chemical formula 3. Forexample, Z₁ may be a hydrogen atom, each of Z₂ and Z₄ may be —CH₃, andZ₃ may be —OCH₃ in chemical formula 3. Portions represented by a boxrepresent the carrier substrate CS.

When the silane compound is self-assembled on the carrier substrate CS,the carrier substrate CS may be cleaned. The carrier substrate CS may becleaned by a cleaning solution, e.g., deionized water or purified water.During the cleaning process, an overcoat compound having a functionalgroup may be used. The functional group of the overcoat compound mightnot react with the functional group on the surface of the carriersubstrate CS, and foreign substances may be removed. Portions of thesilane compound, which are irregularly aligned or stacked, may beremoved during the cleaning process. Accordingly, the silane compoundmay be formed as a uniform monolayer on the carrier substrate CS.

As described above, the self-assembled monolayer may be formed byperforming silanization in a liquid state or a gaseous state, butexemplary embodiments of the present invention should not be limitedthereto or thereby.

Referring to FIGS. 1 and 2B, the inorganic adhesive layer ADL may bedisposed on the debonding layer DBL. The inorganic adhesive layer ADLmay attach the process substrate PS to the debonding layer DBL. Theinorganic adhesive layer ADL may have a hydrophilicity greater than thatof the debonding layer DBL. The inorganic adhesive layer ADL may beformed by the deposition of a metal oxide material containing Al₂O₃and/or AlZnO.

The inorganic adhesive layer ADL may have an island shape when viewed ina plan view. That is, the inorganic adhesive layer ADL may be formed onthe debonding layer DBL in a plurality of regions that are spaced apartfrom each other. The inorganic adhesive layer ADL may overlap a portionof the debonding layer DBL. A material included in the inorganicadhesive layer ADL may be hydrophilic. Thus, the inorganic adhesivelayer ADL may be formed to have the island shape while the debondinglayer DBL is formed.

The debonding layer DBL may be hydrophobic. Accordingly, when thedebonding layer DBL is disposed on the carrier substrate CS without theinorganic adhesive layer ADL disposed on the process substrate PS, theprocess substrate PS might not be suitably placed on the carriersubstrate CS. The inorganic adhesive layer ADL may include a hydrophilicmaterial having lyophilicity with respect to the process substrate PS,and thus the process substrate PS may be stably placed on the carriersubstrate CS by the inorganic adhesive layer ADL. The term of “stablyplaced” used herein may mean that the process substrate PS makes contactwith the carrier substrate CS, and that the process substrate PS and thecarrier substrate CS are chemically covalently-bonded.

Referring to FIGS. 1 and 2C, the process substrate PS may be formed onthe debonding layer DBL. The process substrate PS may be formed byforming a curable polymer layer on the debonding layer DBL and thecarrier substrate CS and curing the polymer layer.

The curable polymer layer may be formed on the carrier substrate CSusing various methods, e.g., a slit coating method or an inkjet method.

The curable polymer layer may include a polymerizable material, such asa monomer, a dimer, an oligomer or a chemical precursor. The curablepolymer layer may be formed by curing a monomer, a dimer, an oligomer,or a chemical precursor.

The curable polymer layer may include polyethylene terephthalate (PET),polyethylene naphthalate (PEN), polyether sulfone (PES), polycarbonateester (PC), polysulfone, phenolic resin, epoxy resin, polyester,polyimide, polyetherester, polyetheramide, cellulose acetate, aliphaticpolyurethane, polyacrylonitrile, polytetrafluoroethlenes, polyvinylidenefluorides, poly(methyl(x-methacrylates)), aliphatic or cyclicpolyolefin, polyarylate, polyetherimide, polyimide, fluoropolymer (likeTeflon), poly(etherether ketone), poly(ether ketone), poly(ethylenetetrafluoroethylene) fluoropolymer), poly(methyl methacrylate), and/orarylate/methacrylatecopolymer. For example, in an exemplary embodimentof the present invention, the curable polymer layer may includepolyimide.

The process substrate PS may be a rigid substrate, but a portion of theprocess substrate PS may be a soft substrate having flexibility. Forexample, the entire process substrate PS may be flexible over the entirearea thereof. The process substrate PS may have a flexible portion andan inflexible portion. The process substrate PS may include a rigid areathat is flexible and a soft area that is not flexible. In an exemplaryembodiment of the present invention, the terms “flexible,” “inflexible,”“having flexibility” and “having no flexibility” or “soft” and “rigid”may be relative terms which represent a property of the processsubstrate PS. The terms “inflexible,” “having no flexibility” and“rigid” may indicate that the portion of the process substrate PS doesnot have flexibility, or has less flexibility than that of the softarea.

Referring to FIGS. 1 and 2D, the device DV may be formed on the processsubstrate PS.

The device DV may be various devices, such as, for example, a memorydevice or a pixel, according to the apparatus to be manufactured.

The process substrate PS may be disposed on the carrier substrate CSwhen the device DV is formed.

In an exemplary embodiment of the present invention, the device DV maybe a pixel applied to a display device. The pixel may include a linepart, a thin film transistor connected to the line part, an electrodeswitched by the thin film transistor, and an image display layercontrolled by the electrode.

The line part may include a plurality of gate lines and a plurality ofdata lines crossing the gate lines.

A plurality of thin film transistors may be included in a passive oractive matrix system. When a plurality of thin film transistors isincluded in the active matrix system, each thin film transistor may beconnected to a corresponding gate line and a corresponding data line.

A plurality of electrodes may be included and each electrode may beconnected to a corresponding thin film transistor.

Although not shown in figures, each thin film transistor may include agate electrode, an active layer, a source electrode, and a drainelectrode. The gate electrode may be branched from a corresponding gateline. The active layer may be insulated from the gate electrode and thesource and drain electrodes may be formed on the active layer to exposea portion of the active layer. The source electrode may be branched froma corresponding data line.

The image display layer may be a liquid crystal layer, anelectrophoretic layer, an electrowetting layer or an organic lightemitting layer according to the method of displaying the image. Theimage display layer may be driven in response to voltage(s) applied tothe electrode(s). The pixel will be described in more detail below.

Referring to FIGS. 1 and 2E, the process substrate PS may be separatedfrom the carrier substrate CS.

When the inorganic adhesive layer ADL includes a hydrophilic material,the process substrate PS may be separated from the carrier substrate CStogether with the inorganic adhesive layer ADL.

In an exemplary embodiment of the present invention, the separation ofthe process substrate PS from the carrier substrate CS should not belimited to a specific method. For example, the process substrate PS maybe separated from the carrier substrate CS by inserting a wedge or aknife into between the process substrate PS and the carrier substrate CSand applying a force in a direction substantially vertical to an outersurface of the process substrate PS and/or the carrier substrate CS.

The process substrate PS and the carrier substrate CS may be separatedfrom each other by attaching a separation member on each outer surfaceof the process substrate PS and the carrier substrate CS and outwardlyapplying a force to the separating member along a directionsubstantially vertical to an outer surface of the process substrate PSand the carrier substrate CS.

In the separation of the process substrate PS and the carrier substrateCS, the adhesive force between the process substrate PS and the carriersubstrate CS may become weaker when the process substrate PS includesthe debonding layer DBL. Van der waals forces and/or electrostaticforces may act between the debonding layer DBL and the carrier substrateCS, and thus an attractive force may act between the process substratePS and the carrier substrate CS. When a difference in surface energybetween the process substrate PS and the carrier substrate CS is largeand the debonding layer DBL of the process substrate PS is hydrophobic,the attractive force may be smaller. Therefore, the process substrate PSmay be separated from the carrier substrate CS with a relatively smallforce, and the process substrate PS may be prevented from being damagedwhen the process substrate PS is separated from the carrier substrateCS.

When a flexible substrate is loaded onto robot arms in order to transferthe flexible substrate, the flexible substrate may be bent and droppeddown from the robot arms.

According to exemplary embodiments of the present invention the devicemay be manufactured on the process substrate PS while the processsubstrate PS is attached to the carrier substrate CS, and thus thedevice may be stably formed on the process substrate PS, which may beflexible. The process substrate PS may be separated from the carriersubstrate CS. The debonding layer DBL may be formed on the carriersubstrate CS. The debonding layer may include a metal oxide materialand/or the silane compound. The inorganic adhesive layer ADL may beformed on the debonding layer DBL. An attractive force acting betweenthe process substrate PS and the carrier substrate CS may be maintainedat a desired level, so that the device DV may be formed and thedebonding of the process substrate PS and the carrier substrate CS maybe performed.

According to an exemplary embodiment of the present invention, damagecaused to the process substrate PS when the process substrate PS isseparated from the carrier substrate CS may be reduced.

According to an exemplary process, a laser beam may be radiated onto ainterface between a process substrate and a carrier substrate toseparate the process substrate from the carrier substrate, or an organicpolymer layer may be formed on the carrier substrate as a debondinglayer. However, the transparency of the process substrate irradiatedwith the laser beam may be reduced and a life span of devices vulnerableto the laser beam may be shortened. When the organic polymer layer isused as the debonding layer, a gas may be discharged from the organicpolymer layer during a high temperature process performed to cure theprocess substrate or to form the device. As a result, bubble defects mayoccur in the process substrate.

When a laser beam is not used according to an exemplary embodiment ofthe present invention, the process substrate PS may be prevented frombeing damaged. When the debonding layer DBL and the inorganic adhesivelayer ADL are included in the device substrate, the amount of gasdischarged from the debonding layer DBL and the inorganic adhesive layerADL may be smaller than that of an organic polymer layer, therebyreducing the occurrence of bubble defects.

FIG. 3 is a graph showing a weight of a process substrate as a functionof a temperature in a process substrate manufactured by the devicesubstrate manufacturing method according to an exemplary embodiment ofthe present invention. In FIG. 3, a variation in weight of the curablepolymer layer has been represented while a temperature is increased onthe assumption that an initial weight of the curable polymer layerformed on the carrier substrate is 100 percent.

Referring to FIG. 3, when the temperature is equal to or smaller thanabout 100° C., the weight of the process substrate is decreased as thetemperature is increased. This is because a solvent in the curablepolymer layer is evaporated when the curable polymer layer starts to becured. However, when the temperature becomes greater than about 100° C.,the weight of the process substrate is not substantially changed. Thisis because no additional gas is discharged from the curable polymerlayer even though the temperature becomes greater than about 100° C.

Accordingly, although the process substrate is exposed to the hightemperature when the device is formed on the process substrate after theprocess substrate is manufactured, gas might not be discharged.Therefore, bubble defects caused by discharged gas do not occur.

According to an exemplary embodiment of the present invention, theinorganic adhesive layer ADL may be formed on the carrier substrate CSin the island shape, but it should not be limited to the island shape.That is, the inorganic adhesive layer ADL may be formed over the entiresurface of the carrier substrate CS.

FIG. 4 is a cross-sectional view showing an inorganic adhesive layerformed on a carrier substrate according to exemplary embodiments of thepresent invention.

Referring to FIG. 4, the inorganic adhesive layer ADL may be formed overthe entire surface of the carrier substrate CS. The inorganic adhesivelayer ADL may have a thickness that is thicker than that of theinorganic adhesive layer ADL shown in FIG. 2B. In the device substratemanufacturing method according to an exemplary embodiment of the presentinvention, the process substrate PS may be stably disposed on thecarrier substrate CS by the inorganic adhesive layer ADL, and theprocess substrate PS may be separated from the carrier substrate CSafter the device is formed.

The use of the device substrate manufacturing method according toexemplary embodiments of the present invention should not be limited toa specific field and the device substrate manufacturing method may beused to form devices on a thin substrate. For example, the displaydevice may be manufactured by using the device substrate manufacturingmethod.

Hereinafter, the display device manufactured by the display devicemanufacturing method according to an exemplary embodiment of the presentinvention will be described in more detail.

FIG. 5 is a cross-sectional view showing a display device manufacturedby a display device manufacturing method according to an exemplaryembodiment of the present invention.

Referring to FIG. 5, the display device may include a first substrateSUB1, a second substrate SUB2 facing the first substrate SUB1, and apixel PXL disposed between the first substrate SUB1 and the secondsubstrate SUB2.

The first substrate SUB1 may include a first surface and a secondsurface, which are opposite to each other. The first surface of thefirst substrate SUB1 may face the second substrate SUB2.

The pixel PXL may be disposed on the first substrate SUB1. The pixel PXLmay include one or more electrodes and an image display layer driven bythe electrode. When the display device is a liquid crystal displaydevice, the electrode may include two electrodes spaced apart from eachother, e.g., a first electrode and a second electrode. The first andsecond electrodes may form an electric field. The first electrode may bereferred to as a pixel electrode PE and the second electrode may bereferred to as a common electrode CE. As shown in FIG. 5, the first andsecond electrodes may be represented as the pixel electrode PE and thecommon electrode CE, respectively, and the image display layer may berepresented as a liquid crystal layer LC.

The second substrate SUB2 may include a third surface and a fourthsurface, which are opposite to each other. The third surface of thesecond substrate SUB2 may face the first surface of the first substrateSUB1.

The second substrate SUB2 may include a same or different material asthe first substrate SUB1. For example, in an exemplary embodiment of thepresent invention, the first and second substrates SUB1 and SUB2 mayinclude polyimide, but they should not be limited thereto or thereby.According to an exemplary embodiment of the present invention, the firstsubstrate SUB1 may include polyimide and the second substrate SUB2 mayinclude polyethersulfone.

A sealing part SL may be disposed between the first substrate SUB1 andthe second substrate SUB2. The sealing part SL may be disposed alongedges of the first and second substrates SUB1 and SUB2 when viewed in aplan view. The sealing part SL may seal the liquid crystal layer LC.

In an exemplary embodiment of the present invention, the secondsubstrate SUB2 may face the first substrate SUB1, but the secondsubstrate SUB2 may be omitted. For example, the pixel PXL may bedisposed on the first substrate SUB1 and a sealing layer may be formedon the pixel PXL.

Although not shown in the figures, the pixel PXL may include a line partand a thin film transistor. The line part may include gate lines anddata lines and the thin film transistor may be connected to the gatelines and the data lines. The thin film transistor may be connected tothe pixel electrode PE of the pixel.

First and second inorganic adhesive layers ADL1 and ADL2 may berespectively disposed on the second surface of the first substrate SUB1and the fourth surface of the second substrate SUB2.

When a gate signal is applied to the gate line, the thin film transistormay be turned on. A data signal applied to the data line may be appliedto the pixel electrode PE through the turned-on thin film transistor.When the data signal is applied to the pixel electrode PE, an electricfield may be formed between the pixel electrode PE and the commonelectrode CE. Liquid crystal molecules of the liquid crystal layer LCmay be aligned by the electric field generated by a difference involtages between a voltage applied to the pixel electrode PE and avoltage applied to the common electrode CE. A transmittance of the lightpassing through the liquid crystal layer LC may be changed, and thus adesired image may be displayed.

FIGS. 6A to 6F are cross-sectional views showing the display devicemanufacturing method of FIG. 5. The following descriptions may focus ondifferent features from the features described above.

Referring to FIG. 6A, a first debonding layer DBL1 may be formed on afirst carrier substrate CS1 and a second debonding layer DBL2 may beformed on a second carrier substrate CS2. Each of the first and seconddebonding layers DBL1 and DBL2 may include the silane compound layer.

Referring to FIG. 6B, a first inorganic adhesive layer ADL1 may beformed on the first debonding layer DBL1 and a second inorganic adhesivelayer ADL2 may be formed on the second debonding layer DBL2.

Referring to FIG. 6C, the first substrate SUB1 may be formed on thefirst carrier substrate CS1, on which the first debonding layer DBL1 andthe first inorganic adhesive layer ADL1 are formed. The first substrateSUB1 may be a process substrate. The second substrate SUB2 may be formedon the second carrier substrate CS2, on which the second debonding layerDBL2 and the second inorganic adhesive layer ADL2 are formed. The secondsubstrate SUB2 may be a process substrate.

Referring to FIG. 6D, various devices including a pixel electrode PE maybe formed on the first substrate SUB1. A common electrode CE may beformed on the second substrate SUB2.

The pixel electrode PE may be formed by depositing a transparentconductive material on the first substrate SUB1 and patterning thetransparent conductive material using a photolithography process. Thecommon electrode CE may be formed by depositing a transparent conductivematerial on the second substrate SUB2 and patterning the transparentconductive material using a photolithography process. The line part andthe thin film transistor may be formed on the first substrate SUB1, andthe gate lines, the data lines, and the thin film transistor may beformed by performing a photolithography process several times. However,the method of forming the pixel electrode PE and the common electrode CEshould not be limited to a particular process.

The processes of forming the pixel electrode PE, the common electrodeCE, the gate lines, the data lines, and the thin film transistor may beperformed on the first and second substrates SUB1 and SUB2,respectively. The first and second substrates SUB1 and SUB may besupported by the first and second carrier substrates CS1 and CS2. Thus,although the first and second substrates SUB1 and SUB2 may be thinand/or flexible, the first and second substrates SUB1 and SUB2 may bemaintained in a flat state by the first and second carrier substratesCS1 and CS2.

Referring to FIG. 6E, the liquid crystal layer LC may be formed betweenthe first and second substrates SUB1 and SUB2. The liquid crystal layerLC may be formed by a one drop filling (ODF) scheme. A sealant SL may bedisposed at edges of the first and second substrates SUB1 and SUB2 toprevent the liquid crystal layer LC from leaking. The sealant SL may bedisposed on the first substrate SUB1 or the second substrate SUB2 beforethe liquid crystal layer LC is formed between the first and secondsubstrates SUB1 and SUB2 and cured after the liquid crystal layer LC isformed between the first and second substrates SUB1 and SUB2, therebysealing the liquid crystal layer LC.

Referring to FIG. 6F, the first and second carrier substrates CS1 andCS2 may be removed from the display device. The first carrier substrateCS1 may be separated from the first substrate SUB1 and the secondcarrier substrate CS2 may be separated from the second substrate SUB2.The separations of the first and second carrier substrates CS1 and CS2from the first and second substrates SUB1 and SUB2 may be performedaccording to the exemplary methods described above.

In an exemplary embodiment of the present invention, the separation ofthe first carrier substrate CS1 from the first substrate SUB1 and theseparation of the second carrier substrate CS2 from the second substrateSUB2 may be performed by the first and second debonding layers DBL1 andDBL2. When surfaces of the display device corresponding to the first andsecond debonding layers DBL1 and DBL2 are hydrophobic, the adhesiveforces between the first substrate SUB1 and the first carrier substrateCS1 and between the second substrate SUB2 and the second carriersubstrate CS2 may be relatively weak.

While the present invention has been particularly shown and describedwith reference to exemplary embodiments thereof, it will be understoodby those of ordinary skill in the art that various changes in form anddetail may be made therein without departing from the spirit and scopeof the present invention.

What is claimed is:
 1. A method of manufacturing a device substrate,comprising: forming a debonding layer on a carrier substrate; forming aninorganic adhesive layer on at least a portion of the debonding layer;forming a process substrate on the carrier substrate; forming a deviceon the process substrate; and separating the process substrate from thecarrier substrate.
 2. The method of claim 1, wherein the debonding layerhas a hydrophobicity greater than a hydrophobicity of the processsubstrate.
 3. The method of claim 2, wherein the debonding layercomprises a silane compound.
 4. The method of claim 3, wherein thesilane compound comprises polydimethylsiloxane (PDMS).
 5. The method ofclaim 3, wherein the forming of the debonding layer further comprises:forming a silane compound layer including a self-assembled monolayer onthe carrier substrate; and cleaning the carrier substrate.
 6. The methodof claim 1, wherein the inorganic adhesive layer has a hydrophilicitygreater than a hydrophilicity of the debonding layer.
 7. The method ofclaim 6, wherein the inorganic adhesive layer comprises a metal oxidematerial.
 8. The method of claim 7, wherein the metal oxide materialcomprises Al₂O₃ or AlZnO.
 9. The method of claim 7, wherein theinorganic adhesive layer is formed by depositing the metal oxidematerial on the debonding layer.
 10. The method of claim 9, wherein theinorganic adhesive layer has an island shape, and wherein the inorganicadhesive layer overlaps a portion of the debonding layer.
 11. The methodof claim 9, wherein the inorganic adhesive layer is formed over anentire surface of the debonding layer.
 12. The method of claim 1,wherein the forming of the process substrate comprises: forming acurable polymer layer on the carrier substrate on which the debondinglayer and the process substrate are formed; and curing the curablepolymer layer.
 13. The method of claim 12, wherein the process substratecomprises polyethylene terephthalate (PET), polyethylene naphthalate(PEN), polyether sulfone (PES), polycarbonate ester (PC), polysulfone,phenolic resin, epoxy resin, polyester, polyimide, polyetherester,polyetheramide, cellulose acetate, aliphatic polyurethane,polyacrylonitrile, polytetrafluoroethlenes, polyvinylidene fluorides,poly(methyl(x-methacrylates)), aliphatic or cyclic polyolefin,polyarylate, polyetherimide, polyimide, fluoropolymer (like Teflon),poly(etherether ketone), poly(ether ketone), poly(ethylenetetrafluoroethylene) fluoropolymer), poly(methyl methacrylate), orarylate/methacrylatecopolymer.
 14. The method of claim 13, wherein theprocess substrate comprises polyimide.
 15. A display device, comprising:a first substrate including a first surface and a second surfaceopposite to the first surface; a pixel disposed on the first surface;and a first inorganic adhesive layer disposed on the second surface,wherein the first inorganic adhesive layer is hydrophobic.
 16. Thedisplay device of claim 15, further comprising: a second substrateincluding a third surface facing the first substrate and a fourthsurface opposite to the third surface; and a second inorganic adhesivelayer disposed on the fourth surface, wherein the second inorganicadhesive layer is hydrophobic.
 17. The display device of claim 16,wherein the first and second inorganic adhesive layers comprise a metaloxide material.
 18. The display device of claim 17, wherein the metaloxide material comprises Al₂O₃ or AlZnO.
 19. A device substrate,comprising: a carrier substrate; a debonding layer disposed on thecarrier substrate, wherein the debonding layer is hydrophobic, andwherein the debonding layer comprises a silane compound; an inorganicadhesive layer disposed on the debonding layer, wherein the inorganicadhesive layer is hydrophilic; and a process substrate disposed on theinorganic adhesive layer.
 20. The device substrate of claim 19, whereinthe inorganic adhesive layer is only formed on a portion of thedebonding layer.